From the prior art, various parking locks for automatic transmissions are known. DE 101 44 063 B4 describes a parking lock which comprises a pawl and a retaining ring on the drive output shaft of an automatic transmission. The pawl can be pivoted from a neutral position to a locking position in which the pawl engages in a retaining recess in the retaining ring and so locks the drive output shaft. To actuate the pawl a pivotable selector lever is provided to which a positioning rod is articulated on which, in turn, two rollers are arranged, which cannot be displaced but can rotate. The positioning rod and the rollers form an actuating element. By swiveling the selector lever, the positioning rod is moved. When the positioning rod moves, the first roller rolls along a fixed wall while the second roller rolls along a ramp of the pawl. By way of the support of the first roller against the fixed wall and the rolling of the second roller up the ramp, the pawl is pivoted in the direction of the retaining ring into its locking position.
From DE 101 31 735 A1, a similar parking lock is known, whose structure, however, is more complex. In this case, the two rollers are not arranged on the positioning rod, but on an actuating carrier which, moreover, is guided and moves within a guide fixed to the housing. The positioning rod, the actuating carrier with the rollers and the guide fixed to the housing form an actuating element. The control is only connected with the actuating carrier inasmuch as the movement of the positioning rod can be transferred to the actuating carrier when the positioning rod is displaced. Furthermore, the actuating carrier can be displaced, relative to the positioning rod along a predetermined path in the longitudinal direction of the latter. The actuating carrier is pre-stressed in a predetermined position relative to the positioning rod. If the pawl, when it pivots, encounters a retaining tooth of the retaining ring, then although the positioning rod can be moved, the actuating carrier is at first only displaced relative to the positioning rod, until the pawl encounters a retaining recess in which it can engage. When this happens, then owing to the pre-stress, the actuating carrier is also moved to its original position in which it presses or swivels the pawl into the locking position.
Although the aforesaid prior art has the advantage that the ability of the actuating carrier to move longitudinally also enables the positioning rod to be displaced when the pawl is resting directly on a retaining tooth, it also has disadvantages. The actuating carrier comprises several components with various connection points so the design is expensive and prone to malfunction. Furthermore, the known actuating element takes up considerable structural space so that it cannot be used for axial pawl actuation or only so with difficulty.
Accordingly, the purpose of the present invention is to provide an actuating element for the parking lock of a transmission, which can be made easily, is not prone to malfunction and takes up little structural space. A further purpose of the invention is to provide a parking lock with an advantageous actuating element of that type.